Ultrasonic cleaning device with temperature responsive cut-off

ABSTRACT

A receptacle for the articles to be cleaned is provided with a heat conducting collar having two outwardly directed wings. A transistor is secured to one wing and a temperature responsive switch is secured to the other. A piezoelectric crystal is secured to the bottom of the receptacle between the wings. As the articles are being cleaned, the temperature rises along the collar from heating of the transistor wing. when the temperature rise propagating to the sensor wing reaches a predetermined value, the switch means shuts-off the device.

United States Patent 1 Cummins et al.

[451 Dec. 3, 1974 ULTRASONIC CLEANING DEVICE WITH TEMPERATURE RESPONSIVE CUT-OF F Inventors: Millard M. Cummins; Robert G.

Best; Thomas Hankins, all of Columbus, Ohio Assignee:

Columbus, Ohio' Filed: Sept. 18, 1973 Appl. No.: 398,437

US. Cl 259/72, 219/311, 219/328, 259/D1G. 44, 259/D1G. 18 Int. Cl. B01f 11/02, 1301f 15/06 Field of Search 259/72, DIG. 41, DIG. 44, I

259/D1G. l8; 134/1, 184; 219/311, 328

References Cited UNITED STATES PATENTS Jacke 259/D1G. 44

Thurman Manufacturing Company,

Cummins 134/184 X Waterloo 259/D1G. 18 X Primary Examiner-Harvey C. Hornsby Assistant ExaminerAlan Cantor Attorney, Agent, or FirmCushman, Darby & Cushman [5 7 ABSTRACT A receptacle for the articles to be cleaned is provided with a heat conducting collar having two outwardly directed wings. A transistor is secured to one wing and a temperature responsive switch is secured to the other. A piezoelectric crystal is secured to the bottom of the receptacle between the wings. As the'articles are being cleaned, the temperature rises along the collar from heating of the transistor wing. when the tem perature rise propagating to the sensor wing reaches a predetermined value, the switch means shuts-off the device.

3 Claims, 3 Drawing Figures ULTRASONIC CLEANING DEVICE WITH TEMPERATURE RESPONSIVE CUT-OFF BACKGROUND OF THE INVENTION The present invention is an outgrowth of the invention disclosed in Cummins, Hankins, Best and Biesecker, U.S. Pat. No. 3,720,402, issued Mar. l3, 1973. The prior'art considered and mentioned in that patent are among the background of the present invention.

When soft contact lenses were first developed and marketed, some could be damaged when heated to above 70C. Heating is believed to be a key to more efficacious aseptization of the lenses, so the lenses as currently formulated can be heated to about 70C. while being cleansed. This has enhanced the advantageousness of ultrasonic cleaning of such lenses; if the temperature of the cleansing solution is permitted to rise to 70 to 75, the typical cleansing time may be correspondingly shortened to to 30 minutes. For mobile people, what can be done most quickly is more likely to get done; Accordingly, the improvement repre 'sented in the present invention can foster better personal care by wearers of soft contact lenses.

SUMMARY OF THE PRESENT INVENTION A receptacle for the articles to be cleaned is provided with a heat conducting collar having two outwardly directed wings. A transistor is secured to one wing and a temperature responsive switch is secured to the other. A piezoelectric crystal is secured to the bottom of the receptacle between the wings. As the articles are being cleaned, the temperature rises along the collar from heating of the transistor wing. When the temperature rise propagating'to the sensor wing reaches a predetermined value, the switch means shuts-off the device.

When used as a cleaner-aseptizer for soft contact lenses, the predetermined cut-off temperature preferably lies in the range of 70 to 80C, the currently favored cutoff temperature is 75C. In equipment of the type and size illustrated, the typical new pair of soft contact lenses cleansed in accordance with the present invention, up to a cut-off temperature in that range are with an electrical insulator and-providing the floor 16' -vate pushbutton 32 which energizes relay coil 70 and through resister 68, diode 67, and normally closed contacts of the temperature responsive switch relay contacts 68 close which maintain current to relay coil 70 even after pushbutton 32 is released; after heating to a preselected temperature, contacts 30 of temperature responsive switch open deenergizing relay 70 which open relay contacts 69 thus removing power from the entire unit. The switch 30 is one which will remain closed until itreceives a signal that heating to a preselected temperature has been reached. A suitable switch is identified by manufacturer and model number as follows:

Switchcraft, type 951.

effectively cleansed to an again safe to wear condition BRIEF DESCRIPTION OF THE DRAWING IN THE DRAWING:

FIG. 1 is a longitudinal, vertical sectional view of the device; v

FIG. 2 is a transverse horizontal, fragmentary sectional view on the line 22 of FIG. 1; and

FIG. 3 is a typical schematic diagram of the electronic components and circuiting of the device..

DETAILED DISCUSSION OF THE "PRESENTLY PREFERRED EMBODIMENT OF THE INVENTION The ultrasonic cleaning. device 10 for small articles such as soft contact lenses includes a housing 12 shown including a first portion 14 made of aluminum coated.

The switch may be one which is pre-set to deactivate at sensation of a factory-decided temperature; more than one such pre-set switch may provided pre-set to deactivate at a corresponding variety of factorydecided temperatures, or a variable cut-off temperature model of switch may be used, if it is selected to provide for effective cleansing at its lowest cut-off temperature and for substantially nondestructive cleansing at its highest temperature, for the typical aritcles intended to be cleaned.

The switch 30, when closed, completes electrical circuitry 38 (FIG. 3) to a piezoelectric crystal 40.

As is apparent, the device may be plugged into a normal residential electrical outlet; the input to the crystal 40 is typically 318 k.c., 130 v., 10 m.a. An operating frequency of 250 to 350 khz. is preferred for the device illustrated. The frequency at which the device operates most effectively is that frequency where mechanical resonance is achieved. The mechanical resonance is that of the assembly comprising the beaker, the heat sink which is cemented to the beaker, the crystal which is cemented to the beaker, and the components which are attached to the heat sink as well as the fluid in the beaker, all of which comprise a mass which has a frequency of mechanical resonance. 'With the described design in the aforementioned patent of Cummins et al, this frequency was to khz. With different designs or different masses used in, say, the heat sink, the frequency of the mechanical resonance would be changed as will be understood by those skilled in the art. The circuitry may be adapted to produce a comparable input where the distributed electric power is different or to provide an altered input where a crystal having The cleansing receptacle 46 is preferably glass, and preferably made of laboratory glassware that can withstand heat shock and mechanical shock. A Pyrex" beaker, ml. size, is very acceptable. The dimensions of such a beaker are about 28 mm. O.D.; about 40 mm. height and about 0.05 inch wall thickness.

The receptacle 46 is disposed in the opening 42 so that most of the receptacle lies within the housing. The receptacle is secured near its mouth to the housing perimetrally of the opening 42 by means such as epoxy resin. The piezoelectric crystal 40 is secured on the bottom of the receptacle 46 using means such as epoxy resin 50.

Within the housing an annular collar 48 of heat conducting material such as brass is secured by e.g. epoxy resin 50 the exterior of the side wall 52 of the receptacle 46 so that it closely circumferentially surrounds the receptacle. I i

The collar 48 is shown having two integral wings 54, 56. Although these are depicted being a pair of diametrically oppositely directed tabs, they need neither be so correspondingly sized nor oriented in order to provide the functions they are called to provide.

Electrically operated heat producing means such as a transistor 63 is mounted on the wing 54 of the collar 48. The temperature sensing means 60 for the switch 30 is disposed on the other wing, 56, and communicated to the switch 30 at 62.

A cover 64 removably surmounts the upper end of the receptacle. It is shown having locater tabs which depend slightly into the receptacle in slight engagement with the inner peripheral surface of the sidewall of the receptacle. The cover is of sufficient weight that it is kept in place by gravity during use of device, although the device could be operated successfully with the cover off. In the latter instance, some fluid loss might occur. I

Although the lenses could be placed directly in the cleaning solution S within the receptacle, it is recommended that they be cleaned while disposed in an openwork, i.e.foraminous container, typically one C made of molded plastic. Such a container is currently supplied with its soft contact lenses by one or more suppliers of soft contact lenses. The container C has two hinged doors 66, one on each side, each removably closing a compartment in which one lens may be placed. The compartments are marked clearly to make it difficult to place the wearers left lens in the compartment marked for receipt of his right lens, and vice versa.

The device 10 could be used to clean other heat sensitive articles, however, it is especially well suited to clean soft contact lenses. The way the receptacle, heat sink and the housing are put together minimizes the prospect that the device will be used improperly, or idly tampered with. The design allows the device 10 to be made so inexpensively and so durably that is has a good potential for being successfully mass marketed. All the user has to do is place his or her lenses in a familiar container, place cleansing solution in the receptacle, place the container in the receptacle, replace the cover and actuate the knob 32 to close the switch 30. As the crystal 40 produces ultrasonic vibrations in the cleansing solution, heat is produced by the transistor 63 and,

to a lesser extent, by operation of the crystal 40 and with passage of time, is conducted with generally predictable losses out the wing 56. When the temperature rises to a preselected cut-off temperature, as sensed at 60, the switch 30 automatically opens. Because of the heat losses, in the typical example depicted, when the lenses have reached a desired cut-off temperature C. in the ultrasonically vibrating cleansing solution, the sensor 60 has sensed a cutoff temperature of 75,

whereupon the switch 30 automatically opens.

A low-powered indicator light may be provided on the front of the device and wired into the circuitry 38 to be lit'so long as the switch 30 remains closed, as a visible indication that the device 10 is operating.

Accessory elements may be provided. For instance, the circuit '38 may be provided witha timer cut-off the cleansing operation after a preselected time, i.e. as a safety featureto ensure that an unattended device 10 does not inadvertently run for too long a time.

It should now be apparentthat the ultrasoniccleaning device with temperature-responsive cut-off as described hereinabove possesses each of the attributes set forth in the specification under the heading Summary of the Invention hereinbefore. Because the ultrasonic cleaning device with temperature responsive cut-off of the invention can be modified tosome extent without departing from the principles of the invention as they have been outlined and explained in this specification, the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the follwing claims.

What is claimed is: i V

1. An ultrasonic cleaning device, comprising:

a receptacle for cleansing fluid; v

a piezoelectric crystal secured on the receptacle for imparting vibrations thereto;

heat conducting collar means on said receptacle;

electrically operated heat producing means secured on the collar means for imparting additional heat to the receptacle via the collar means while the crystal vibrates;

a heat sensor communicated to the collar means distally of the heat producing means so that heat conducted by the collar means during operation of the crystal to produce ultrasonic vibrations in the cleansing fluid eventually raises the temperature sensed by the heat sensor to a predetermined cutoff temperature;

power source means for electrically operating the heat producing means and for electrically exciting the piezoelectric crystal, including a manually actuatable, automatically deactuatable switch, communicated to the heat sensor for automatically deactuating the switch when the predetermined cutoff temperature has been reached. 2. The ultrasonic cleaning device of claim 1 wherein the heat producing means is constituted by a transistor. 3. The ultrasonic cleaning device of claim 1 wherein the switch is constructed to deactuate when the temperature sensed by the heat sensor correlates to a temperature of 70 to C. reached in the cleansing fluid in the receptacle. 

1. An ultrasonic cleaning device, comprising: a receptacle for cleansing fluid; a piezoelectric crystal secured on the receptacle for imparting vibrations thereto; heat conducting collar means on said receptacle; electrically operated heat producing means secured on the collar means for imparting additional heat to the receptacle via the collar means while the crystal vibrates; a heat sensor communicated to the collar means distally of the heat producing means so that heat conducted by the collar means during operation of the crystal to produce ultrasonic vibrations in the cleansing fluid eventually raises the temperature sensed by the heat sensor to a predetermined cutoff temperature; power source means for electrically operating the heat producing means and for electrically exciting the piezoelectric crystal, including a manually actuatable, automatically deactuatable switch, communicated to the heat sensor for automatically deactuating the switch when the predetermined cut-off temperature has been reached.
 2. The ultrasonic cleaning device of claim 1 wherein the heat producing means is constituted by a transistor.
 3. The ultrasonic cleaning device of claim 1 wherein the switch is constructed to deactuate when the temperature sensed by the heat sensor correlates to a temperature of 70* to 80*C. reached in the cleansing fluid in the receptacle. 